During the last 150 years or more, society has witnessed many key scientific discoveries and inventions, which have dramatically improved not only our quality of life, but our lifespan. However, the motivation of scientists to provide scientific advances has generally not been the achievement of these goals, but mainly driven by research curiosity. Fundamental scientific studies, also known as basic science, have paved the way to a society of knowledge by means of continuously evolving education systems, and have led to applied science and technological breakthroughs changing the World. However, without basic science such life-changing advances would not happen, which is poorly understood by the society. Having this in mind, chemists and biochemists working in a chemistry network highlight here examples of how basic science has played a crucial role and led to major breakthroughs. In seven short stories, the authors describe cases and historical events where basic research discoveries have advanced science, and opened avenues for future achievements. Investment in basic science is crucial for a nation’s health and wealth. The support of scientists driven by curiosity ultimately can benefit the whole of society, not only in innovative products, but also in the improvement of the understanding of our own lives.

One experimental strategy to prepare a nitrosyl metal complex is based on the acid-base conversion of NO2- into NO+. Here, we employed UV-vis absorption and FTIR spectroscopies to investigate the reaction of cis-[Ru(NO2)(bpy)2(imN)]PF6 with H3O+, which produced cis-[Ru(NO)(bpy)2(imN)](PF6)3 complex. Chromatographic studies were carried out and showed that immediately after nitrite complex was dissolved only one species was present with retention time(tR) of 6.81 minutes. Addition of H3O+ to nitrite complex led to the formation of one major peak with tR of 3.92 min supporting nitrosyl complex formation. The reaction of nitrosyl complex with cysteine was also monitored by HPLC and it showed clearly the formation and followed decrease of a peak at 3.38 minute with maximum absorption at 380 nm, consistent with an intermediate complex. Later, it was observed the appearance of a peak at 4.15 minute with absorption band at 470 nm. In contrast to the reaction with cysteine, methionine did not show the formation of any intermediate. The use of HPLC was an important tool to support mechanistic assumptions for nitrosyl reactions.

The cis-[Ru(bpy)2(4-bzpy)(NO)](PF6)3 complex was prepared (4-bzpy = 4-benzoylpyridine), and characterized by UV-visible, infrared and nuclear magnetic resonance (NMR) spectroscopies and electrochemical techniques. The reaction with cysteine was preliminarily investigated, aiming to shed light on the potential biological mechanism for NO or HNO release mediated by thiols. Furthermore, photochemical behavior of cis-[Ru(bpy)2(4-bzpy)(NO)](PF6)3 was studied, where it was observed NO release upon ultraviolet, blue and green light irradiations. This latter long wavelength showed still good efficiency, which has not been reported for this type of complex. This feature is very important for a potential application in phototherapy. Additionally, vasorelaxant activity was investigated in rat-isolated aorta. This compound exhibited a greater maximum efficacy than sodium nitroprusside (SNP) as a blood vessel relaxant. Nevertheless, the EC50 for SNP (13.3 nmol L-1) was 52-fold smaller than the EC50 for cis-[Ru(bpy)2(4-bzpy)NO](PF6)3 (690 nmol L-1). Altogether, these results suggest this complex is a promising NO donor agent deserving further biological studies.

The development of NO photoreleaser compounds has important potential applications on medicine, particularly on preventing topic infections and controlling cancers. Due to these expectations, the photochemical release of nitric oxide from complexes of [Ru(bpy)2LX]n+, where L = imidazole, 1-methylimidazole, sulphite and thiourea and X = NO+ and NO2− was investigated employing spectroscopic and electrochemical techniques. The release of NO was confirmed by chronoamperometry using a NO selective electrode, while the other product, mainly [RuIIH2O], was detected by UV-Visible spectroscopy and electrochemical techniques for all complexes except for thiourea. The amount of NO released by these complexes upon irradiation was determined using a new developed method using square wave voltammetry.

Complexos do tipo trans-[Ru(L)(NH3)4(L’)](PF6)n, onde L = 4-cianopiridina (CNpy), NCS-, CN-, e L’ = CNpy, 1,4-ditiano (1,4-dt), 4-mercaptopiridina (pyS) e tionicotinamida (tna), foram sintetizados e caracterizados. SAMs sobre ouro formadas com os complexos que contêm ligantes sulfurados foram estudadas por desorção redutiva e espectroscopia SERS. Dependendo da natureza do ligante L’, a capacidade retiradora do ligante CNpy mostrou ser forte o suficiente para oxidar parcialmente o átomo de rutênio e, em consequência, deslocalizar densidade eletrônica s do ligante localizado em posição trans. Os resultados de desorção redutiva mostraram que a estabilidade das SAMs formadas está diretamente relacionada a este efeito.

Trans-[Ru(L)(NH3)4(L’)](PF6)n type complexes, where L = 4-cyanopyridine (CNpy), NCS-, CN-, and L’ = CNpy, 1,4-dithiane (1,4-dt), 4-mercaptopyridine (pyS) and thionicotinamide (tna), were synthesized and characterized. SAMs on gold of the complexes containing sulfur were studied by reductive desorption and SERS spectroscopy. Depending on the nature of L’, the withdrawing capability of the CNpy ligand is strong enough to partially oxidize the ruthenium atom and, as a consequence, delocalize the s electronic density from the trans located ligand. The reductive desorption results showed that the stability of the SAMs is directly related to this effect.